Unformatted text preview: sfer. That is,
Sgen Stotal Ssys Ssurr 0 Subsystem
1 N ∆ Stotal = Σ ∆ Si > 0 Subsystem
2 i =1 Subsystem
3 Subsystem
N FIGURE 7–6
The entropy change of an isolated
system is the sum of the entropy
changes of its components, and
is never less than zero.
Isolated system
boundary m=0
Q=0
W=0 (7–11) where the equality holds for reversible processes and the inequality for irreversible ones. Note that Ssurr refers to the change in the entropy of the surroundings as a result of the occurrence of the process under consideration.
Since no actual process is truly reversible, we can conclude that some entropy is generated during a process, and therefore the entropy of the universe,
which can be considered to be an isolated system, is continuously increasing.
The more irreversible a process, the larger the entropy generated during that
process. No entropy is generated during reversible processes (Sgen 0).
Entropy increase of the universe is a major concern not only to engineers
but also to philosophers, theologians, economists, and environmentalists since
entropy is viewed as a measure of the disorder (or “mixedupness”) in...
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 Spring '09
 Thermodynamics, Energy, Entropy, entropy change

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